Method for evaluating dependence of properties of semiconductor substrate on plane orientation and semiconductor device using the same

1. A method for evaluating a plane orientation dependence of a semiconductor substrate comprising: forming a hard mask on a semiconductor substrate having plane orientation ( 100 ); anisotropically etching the semiconductor substrate with use of the hard mask as a mask to obtain a surface oriented in a specific crystal orientation, said anisotropic etching being of a reactive ion etching type; and evaluating a plane orientation dependence of properties of the semiconductor substrate by use of at least a portion of the surface oriented in the specific crystal orientation, wherein the evaluating step comprises forming a thermal oxide film on at least a prism-shaped pillar obtained by the reactive ion etching and simultaneously observing the thermal oxide film on both a surface having plane ( 100 ) and a surface having plane ( 110 ).

2. A method claimed in claim 1 , wherein the evaluation of the plane orientation dependence is evaluation of a rate for forming a thermal oxidation film depending on the plane orientation of the semiconductor substrate.

3. A method claimed in claim 1 , wherein said semiconductor substrate has a diamond crystal structure.

4. A method claimed in claim 1 , wherein the surface oriented in a specific crystal orientation is of plane ( 100 ).

5. A method claimed in claim 1 , wherein the hard mask is a circle or symmetric polygon.

6. A method claimed in claim 5 , wherein anisotropically etching is performed to a depth of at least several times the size of the hard mask.

7. A method for aligning a photomask comprising: forming a hard mask on a semiconductor substrate having plane orientation ( 100 ); anisotropically etching the semiconductor substrate with use of the hard mask as a mask to obtain a pillar and/or trench having a surface oriented in a specific crystal orientation; aligning a photomask using the obtained surface of the pillar and/or trench as a reference pattern; and wherein two pillars and/or trenches are obtained in the form of prisms each having a surface oriented in a specific crystal orientation by anisotropic etching, the two pillars and/or trenches being separate from each other, the photomask has a pattern provided with two marks at a spaced interval, the two marks being in a parallel relation and each having two pairs of parallel sides, and the photomask is aligned by putting the sides of the marks of the photomask in parallel with the sides of the pillars and/or trenches.

8. A method for aligning a photomask comprising: forming a hard mask on a semiconductor substrate including plane orientation ( 100 ); anisotropically etching the semiconductor substrate with use of the hard mask as a mask to obtain a pillar and/or trench having a surface oriented in a specific crystal orientation; aligning a photomask using the obtained surface of the pillar and/or trench as a reference pattern; and wherein two pillars and/or trenches are obtained by anisotropic etching, the two pillars and/or trenches being separate from each other, the photomask has a pattern provided with two marks at a spaced interval, the two marks being in a substantially parallel relation and each having substantially parallel sides, and the photomask is aligned by putting the sides of the marks of the photomask substantially in parallel with the sides of the pillars and/or trenches.